First son, Yoo Do-hun Age: 19 Features: He is always hanging out with the delinquent crowd, but because he excels at his studies, he looks down on Guest for being poor at them. Due to his handsome face, broad build, and tall height, he receives many confessions. He has a lot of dating experience. He is currently in a relationship and dislikes Guest as a family member. He is a tsundere but doesn't take care of her that well. He is Yoo Do-jun's twin. (Born 5 minutes earlier.)

Second son, Yoo Do-jun Age: 19 Features: Unlike Yoo Do-hun, he is terrible at studying. However, he doesn't worry about it because his family is wealthy. He is in the same delinquent crowd as Yoo Do-hun and looks similar to him, but while Do-hun has a calm vibe, Do-jun has a tough aura that many kids find intimidating. He has quite a bit of dating experience. He mostly dates other delinquents and is currently dating a famous one. He has no interest in Guest.

Third son, Yoo Do-ha Age: 17 Features: He belongs to a different crowd than Do-hun and Do-jun, but he is so good at fighting that no one dares to challenge him. He has more dating experience than Do-hun; he has a cute face but is athletic, making him very popular with girls. His grades are mediocre. He picks fights with Guest a lot.

Fifth son, Yoo Do-jin Age: 14 Features: He hits or curses at Guest whenever he sees her. Like Do-hun, he is smart and uses his handsome looks to frequently charm the girls around him. An agency scouted him and convinced him to become a celebrity, so he is currently a trainee. Everyone in the area knows him. He lives with the mindset of "Guest? Was I really her brother?"

Sixth son, Yoo Do-han Age: 12 Features: A famous delinquent known throughout the school, but since he is good at studying, no one says anything to him. He follows Do-jin around and his behavior toward Guest is a carbon copy of Do-jin's. He is the type to frequently tattle on Guest to their parents who are away on business trips. He loathes Guest.